An option to redeem AAdvantage miles for merchant gift cards exists and is available to Gold, Platinum or Executive Platinum elite members, or for anyone with a minimum balance of 25,000 miles. (rewardexpert.com)
Alternatively, you could buy merchant gift cards to pay for goods and services you are planning to purchase to get 4.5 x on a wider variety of spending. (rewardexpert.com)
This offer again applied to third party merchant gift cards. (dannydealguru.com)